Graphene-TiO2 nanocomposite photocatalysts for selective organic synthesis in water under simulated solar light irradiation

Heterogeneous photocatalysis offers a promising route to realize green oxidation processes in organic synthesis because such selective organic transformation processes can be enabled under solar light irradiation with ambient conditions. In this research, graphene-TiO2 nanocomposites have been utilized for aerobic selective oxidation of benzylic alcohols to corresponding aldehydes and acids in water under simulated solar light irradiation. The photocatalytic performance and related properties of solvent exfoliated graphene-TiO2 (SEG-TiO2) and reduced graphene oxide-TiO2 (RGO-TiO2) have been comparatively studied. It has been found that decreasing the defect density of graphene, by using SEG instead of graphene oxide (GO) as the precursor of RGO, can enhance the photoactivity of graphene-TiO2 nanocomposites due to the improved electron conductivity of SEG as compared to that of RGO. It is hoped that this work would stimulate further interest in utilizing graphene-semiconductor nanocomposite photocatalysts in the field of green-chemistry-oriented photocatalytic selective organic transformation.